A new physical simulation model was developed to simulate the casting process of the ductile iron heavy section spent-nuclear-fuel container.In this physical simulation model,a heating unit with DR24 Fe-Cr-Al heating ...A new physical simulation model was developed to simulate the casting process of the ductile iron heavy section spent-nuclear-fuel container.In this physical simulation model,a heating unit with DR24 Fe-Cr-Al heating wires was used to compensate the heat loss across the non-natural surfaces of the sample,and a precise and reliable casting temperature controlling/monitoring system was employed to ensure the thermal behavior of the simulated casting to be similar to the actual casting.Also,a mould system was designed,in which changeable mould materials can be used for both the outside and inside moulds for different applications.The casting test was carried out with the designed mould and the cooling curves of central and edge points at different isothermal planes of the casting were obtained.Results show that for most isothermal planes,the temperature control system can keep the temperature differences within 6 ℃ between the edge points and the corresponding center points,indicating that this new physical simulation model has high simulation accuracy,and the mould developed can be used for optimization of casting parameters of spent-nuclear-fuel container,such as composition of ductile iron,the pouring temperature,the selection of mould material and design of cooling system.In addition,to maintain the spheroidalization of the ductile iron,the force-chilling should be used for the current physical simulation to ensure the solidification of casting in less than 2 h.展开更多
Heavy thickness steel plates with a good combination of strength,toughness and weldability have been demanded for building of large container ships.High strength steel plates with heavy gauge of EH36,EH40 and EH47 gra...Heavy thickness steel plates with a good combination of strength,toughness and weldability have been demanded for building of large container ships.High strength steel plates with heavy gauge of EH36,EH40 and EH47 grades were developed by optimizing chemical compositions and TMCP process parameters.Micro alloying elements of Ti and Nb were added to the three steel grades for enhancing the strength and toughness of base plates.The strength of base plates of the EH47 grade was further enhanced with the help of the increased amount of substitutional solid solutes,such as manganese,copper,nickel,or chromium.EH36 steel plates for high heat input over 550 kJ/cm were manufactured by improving thermal stability of TiN particles for better weld heat-affected zone toughness.Thermally stabilized TiN particles effectively suppress grain growth at weld heat-affected zone,leading to better toughness.These steel plates showed excellent mechanical properties of base plates and welded joints.展开更多
In the present work,effects of various heat transfer fluids on the discharging performance of a phase change material(PCM) included cylindrical container are numerically assessed during forced convection.The heat tran...In the present work,effects of various heat transfer fluids on the discharging performance of a phase change material(PCM) included cylindrical container are numerically assessed during forced convection.The heat transfer fluid air,hydrogen,water and nanofluid with alumina particles are used and the the geometric variation of the PCM embedded region is also considered.The finite element method is used as the solver.Dynamic features of heat exchange with various phases are explored for different heat transfer fluid types,Reynolds number(between 100 and 300) and PCM embedded region geometric variation(h_(x)between 0.01 d_(1) and 0.65 d_(1),hybetween 0.1 h_(1) and 0.4 h_(1)).It is observed that discharging time is significantly influenced by the heat transfer fluid type while full phase transition time for air is obtained as more than 10 times when hydrogen is utilized as heat transfer fluid.The best performance is achieved with nanofluid.When the PCM integrated region size is reduced,discharging time is generally reduced while due to the form of the geometry,vortex formation is established in the PCM region.This results in performance degeneration at the highest radius and height of the inner cylinder.Discharging time increases by about 12% when radius of the inner cylinder is increased from h_(x)=0.35 d_(1) to h_(x)=0.45 d_(1).Dynamic features of PCM temperature and liquid fraction are affected with Reynolds number while discharging time is reduced by about 48% when configurations with the lowest and highest Reynolds number are compared.展开更多
针对塑料瓶盖在低温环境下脆性增加,导致生产过程中出现连接桥断裂、高歪盖等现象的问题,开展了塑料瓶盖加热仓的设计与应用研究,对国内目前的瓶盖加热方法进行了分析归纳,提出了一种采用热风机进行在线加热的瓶盖加热仓装置。利用流体...针对塑料瓶盖在低温环境下脆性增加,导致生产过程中出现连接桥断裂、高歪盖等现象的问题,开展了塑料瓶盖加热仓的设计与应用研究,对国内目前的瓶盖加热方法进行了分析归纳,提出了一种采用热风机进行在线加热的瓶盖加热仓装置。利用流体仿真软件Solid Works Flow Simulation建立了加热仓的流体模型,得到了热空气温度分布图和流场分布图。仿真结果表明,加热仓设计合理、温度分布均匀,无加热死角。研究结果表明,该加热仓设计简单合理,可显著减少生产中由于瓶盖引起的饮料质量问题,具有很好的经济效益。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.50974049 and 51174068)the Heilongjiang Postdoctoral Science Foundation of China(Grant No.LBH-Z09009)
文摘A new physical simulation model was developed to simulate the casting process of the ductile iron heavy section spent-nuclear-fuel container.In this physical simulation model,a heating unit with DR24 Fe-Cr-Al heating wires was used to compensate the heat loss across the non-natural surfaces of the sample,and a precise and reliable casting temperature controlling/monitoring system was employed to ensure the thermal behavior of the simulated casting to be similar to the actual casting.Also,a mould system was designed,in which changeable mould materials can be used for both the outside and inside moulds for different applications.The casting test was carried out with the designed mould and the cooling curves of central and edge points at different isothermal planes of the casting were obtained.Results show that for most isothermal planes,the temperature control system can keep the temperature differences within 6 ℃ between the edge points and the corresponding center points,indicating that this new physical simulation model has high simulation accuracy,and the mould developed can be used for optimization of casting parameters of spent-nuclear-fuel container,such as composition of ductile iron,the pouring temperature,the selection of mould material and design of cooling system.In addition,to maintain the spheroidalization of the ductile iron,the force-chilling should be used for the current physical simulation to ensure the solidification of casting in less than 2 h.
文摘Heavy thickness steel plates with a good combination of strength,toughness and weldability have been demanded for building of large container ships.High strength steel plates with heavy gauge of EH36,EH40 and EH47 grades were developed by optimizing chemical compositions and TMCP process parameters.Micro alloying elements of Ti and Nb were added to the three steel grades for enhancing the strength and toughness of base plates.The strength of base plates of the EH47 grade was further enhanced with the help of the increased amount of substitutional solid solutes,such as manganese,copper,nickel,or chromium.EH36 steel plates for high heat input over 550 kJ/cm were manufactured by improving thermal stability of TiN particles for better weld heat-affected zone toughness.Thermally stabilized TiN particles effectively suppress grain growth at weld heat-affected zone,leading to better toughness.These steel plates showed excellent mechanical properties of base plates and welded joints.
文摘In the present work,effects of various heat transfer fluids on the discharging performance of a phase change material(PCM) included cylindrical container are numerically assessed during forced convection.The heat transfer fluid air,hydrogen,water and nanofluid with alumina particles are used and the the geometric variation of the PCM embedded region is also considered.The finite element method is used as the solver.Dynamic features of heat exchange with various phases are explored for different heat transfer fluid types,Reynolds number(between 100 and 300) and PCM embedded region geometric variation(h_(x)between 0.01 d_(1) and 0.65 d_(1),hybetween 0.1 h_(1) and 0.4 h_(1)).It is observed that discharging time is significantly influenced by the heat transfer fluid type while full phase transition time for air is obtained as more than 10 times when hydrogen is utilized as heat transfer fluid.The best performance is achieved with nanofluid.When the PCM integrated region size is reduced,discharging time is generally reduced while due to the form of the geometry,vortex formation is established in the PCM region.This results in performance degeneration at the highest radius and height of the inner cylinder.Discharging time increases by about 12% when radius of the inner cylinder is increased from h_(x)=0.35 d_(1) to h_(x)=0.45 d_(1).Dynamic features of PCM temperature and liquid fraction are affected with Reynolds number while discharging time is reduced by about 48% when configurations with the lowest and highest Reynolds number are compared.
文摘针对塑料瓶盖在低温环境下脆性增加,导致生产过程中出现连接桥断裂、高歪盖等现象的问题,开展了塑料瓶盖加热仓的设计与应用研究,对国内目前的瓶盖加热方法进行了分析归纳,提出了一种采用热风机进行在线加热的瓶盖加热仓装置。利用流体仿真软件Solid Works Flow Simulation建立了加热仓的流体模型,得到了热空气温度分布图和流场分布图。仿真结果表明,加热仓设计合理、温度分布均匀,无加热死角。研究结果表明,该加热仓设计简单合理,可显著减少生产中由于瓶盖引起的饮料质量问题,具有很好的经济效益。
